The present invention generally relates to footwear and, more particularly, to footwear that provides increased stability and cushioning.
In order to reduce the impact forces on knees and ankle joints, current shoe designs incorporate a wide variety of means to cushion the foot. For example, some athletic shoes include air pockets that are incorporated into the sole of the shoe. Other problems addressed by shoe manufacturers, especially athletic shoe manufacturers, include reducing ankle strain due to over rotation. Typically, the ankle is one of the most vulnerable joints in the body, especially when engaging in athletic activities. Ankle sprains occur usually from excessive rotation of the ankle jointxe2x80x94both internal rotation and external rotation of the ankle joint. In an attempt to reduce the risk of ankle injury, athletic shoe manufacturers have designed footwear that restricts both medial and lateral motion of the ankle to thereby limit both internal and external rotation of the ankle. However, by restricting the ankle motion, shoe manufactures often hinder the natural motions of the foot and ankle, which tends to reduce the user""s athletic performance.
Consequently, there is a need to provide footwear that reduces the risk of injury to the wearer, especially to the wearer""s ankle, but in a manner that does not impede the wearer""s performance, whether that performance is an athletic activity, such as running, playing basketball, playing tennis, hiking, playing racket ball, or a non-athletic activity, such as standing, for example at work, therapeutic exercises, or casual walking, or the like.
The present invention provides footwear that reduces the stress on the joints of the wearer and, further, reduces the likelihood of ankle strain.
In one form of the invention, an article of footwear includes a sole, an upper portion, and a suspension system. The upper portion includes a shell for enclosing a user""s foot therein and a collar for extending around the user""s ankle. The suspension system extends between the upper portion and the sole and includes an energy storage and transfer member, which transfers reaction forces from the sole to the shell generally at the collar whereby the energy storage member reduces overturning moment forces on the user""s ankle by converting otherwise potentially overturning forces into stabilizing forces directed to specific locations within the ankle joint.
In one aspect, the article includes a second energy storage member, which is in series with the first energy storage member. For example, the second energy storage member may comprise a compressible body. In a further aspect, the first energy storage member comprises a pair of springs, with one of the springs located at a medial side of the article, and the other spring located at a lateral side of the article. For example, the springs may comprise leaf springs, including plastic leaf springs.
According to another form of the invention, an article of footwear includes a sole and an upper portion coupled to the sole. The sole includes a toe region, a heel region, and a central longitudinal axis. In addition, the sole includes a first lateral axis, which extends generally orthogonal to the longitudinal axis at the heel region, and a second lateral axis, which extends generally orthogonal to the longitudinal axis at the toe region. The sole includes at least one enlarged area, which extends laterally outward from the central longitudinal axis along one of the lateral axes. The sole further includes a tangent line at the enlarged area, which intersects the lateral axis and forms an angle in a range of about 40 degrees to 80 degrees with respect to the lateral axis.
In a further aspect, the shell has a collar for extending around a user""s ankle. In addition, the article preferably includes a suspension system, which extends between the upper portion and the sole. The suspension system includes an energy storage member, which transfers reaction forces from the sole to the shell generally at the collar whereby the energy storage member reduces/counteracts moment forces on the user""s ankle when the user leans or incurs potential overturning forces in the article of footwear.
In another aspect, the enlarged area extends outward along the first lateral axis. Alternately, the enlarged area may extend outward along the second lateral axis. In yet a further aspect, the sole includes two enlarged areas, with one of the areas extending outward along the first lateral axis, and the other extending outward along the second lateral axis.
In yet another form of the invention, an article of footwear includes a sole, an upper portion, which is coupled to the sole, and a suspension system, which extends between the upper portion and the sole. The suspension system includes a first energy storage member and a second energy storage member. The first energy storage member is in series with the second energy storage member, and with the first energy storage member providing a first resistance over a first range of motion for a wearer of the article, and the second energy storage member providing a second resistance over a second range of motion for the wearer of the article.
In one aspect, the first resistance is greater than the second resistance. For example, the first energy storage member preferably provides the first resistance over a range of motion having an angle from about 0xc2x0 to 10xc2x0, while the second energy storage member provides the second resistance over a range of motion having an angle from about 5xc2x0 to 15xc2x0, which creates an overlap of resistance.
In a further form of the invention, an article of footwear includes a sole and an upper portion which forms a shell for enclosing a user""s foot and includes a collar for extending around a user""s ankle. The article further includes a suspension system, which includes a pair of leaf springs that extend between the upper portion and the sole. The leaf springs transfer reaction forces from the sole to the shell generally at the collar whereby the leaf springs reduce moment forces on the user""s ankle when the user leans or experiences potential overturning forces in the article of footwear and further provide cushioning and stability to the user""s joints.
In one aspect, one of the springs is located at the medial side of the upper portion, while the other of the springs is located at the lateral side of the upper portion.
In another aspect, the springs comprise plastic or composite material leaf springs. Optionally, the springs are releasably mounted to the upper portion and the sole whereby the springs are removable for adjustment or replacement
In yet another aspect, the article further includes a cushioning member that is positioned between the upper portion and the sole. The cushion member may, for example, comprise a compressible body such as a liquid or gas filled bladder/compressible container.
These and other objects, advantages, purposes, and features of the invention will become more apparent from the study of the following description taken in conjunction with the drawings.